D = imread('yellowlily.jpg'); %read colour image
figure, imshow(D),title('Original Colour Image'); %show original image
r1 = D(:,:,1); %read the red component
g1 = D(:,:,2);%read the green component
b1 = D(:,:,3);%read the blue component
D(:,:,1) = r1+100; %add fixed constant to the red component
D(:,:,2) = g1+100;%add fixed constant to the green component
D(:,:,3) = b1+100;%add fixed constant to the blue component
figure,imshow(D),title('Contrast Enhanced Colour Image');